Abstract:Spinel LiMn2O4, in which the [Mn2O4] framework provides a three-dimensional interstitial space for Li+ transportation, shows excellent Li+ insertion and extrusion property from the Mn-O lattice. The lithium ion-sieve effect strongly depends on the crystal structure and morphology of the LiMn2O4 precursor, yet, it is difficult to control the crystal morphology via the traditional solid-state reaction since high temperature calcinations; Thus, a much milder hydrothermal condition is optimized to synthesize low-dimensional spinel LiMn2O4 precursor directly using the commercial H2O2, LiOH and Mn(NO3)2 mixed solution and reacting at 110 for 8 h in PTFE-lined stainless steel autoclave, more favorable to control the nanocrystalline structure with well-defined pore size distribution and high surface area; Further, the final MnO2 ion-sieve was easily derived via the acid treatment process to completely extract lithium ions from the spinel LiMn2O4 precursor, without obvious change to the Mn-O lattice structure and the one-dimensional nanorod morphology; The Li+ selective adsorption behaviors of the MnO2 nanorod ion-sieve are improved remarkably compared to those prepared via the conventional solid-state reaction, which is promising for lithium extraction from aqueous solution including brine, seawater and waste water.